Simultaneous braking and steering control method based on nonlinear model predictive control for emergency driving support

Autonomous emergency braking (AEB) has drawn a lot of attention as an active safety system preventing rear-end collision avoidance when the relative speed between vehicles is slow. To increase the operation range of current AEB system, this paper suggests a collision avoidance strategy using steering and braking simultaneously with nonlinear model predictive control (NMPC) method. The NMPC predicts the vehicle’s future trajectory with its open-loop dynamics and calculates the error between the predicted and the desired paths. Then NMPC calculates the control inputs such as the wheel steering angle and vehicle acceleration by optimizing the cost function over future receding horizon with predetermined constraints. In this paper, constraints on the wheel steering angle is proposed in consideration of vehicle’s predicted lateral acceleration, which should be smaller than the threshold in order to maintain lateral vehicle’s stability. To verify the performance of the proposed strategy, two simulation scenarios were tested in MATLAB and CarSim simulation environments.